Emil graf



E.GRAF

SPARK PLUG Dec. 11 1923.

Filed Nov. 16. 1921 y 7 H K INVENTOR. [mil 6522 BY W:

ATTORNEYS.

Patented Dec. 11, 1923.

UNITED STATES PATENT OFFICE.

EMILE GRAF, OF NEW YORK, N. Y., ASSIGNOR, BY MESNE ASSIGNMENTS, TO RUDOLPH STEINACHER, OF NEW YORK, N. Y.

SPARK PLUG,

Application filed November 16, 1921. Serial No. 515,481.

To all whom it may concern Be it known that I, EMIL GRAF, a citizen of the Republic of Switzerland, and a resident of New York, in the county of New I York and State of New York, have invented certain new and useful Improvements in Spark Plugs, of which the following is a specification.

One of the principal objects of this invention is to provide a spark plug to be used upon an internal combustion engine, with an intensifier or condenser arranged within the plug and constructed as an integral part thereof.

Another object is to provide the plug with a reversible electrode which can be quickly and easily reversed to provide a new terminal should the terminal in use become so pitted or corroded as to destroy the efliciency of the plug.

A further object is to so construct the plug that it will be impossible to exert an excessive pressure upon the porcelain of the plug thereby breaking the porcelain and ruining the plug.

Another object is to provide the plug with a replaceable porcelain and electrode if desired.

Another object is to so construct the porcelain adjacent the. projecting point of the electrode, that any oil which may be thrown up against the bottom of the porcelain will tend to flow away from the point of the electrode.

And a further object is to provide a means for readily observing at a glance whether current is being delivered by the source of electrical supply to the plug.

For the accomplishment of these and such further objects as Will hereinafter be apparent to those skilled in the art to which this appertains, the invention consists in the construction, combination and arrangement of parts herein specifically described and illustrated in the accompanying drawings, wherein is shown a preferred embodiment of the invention but it will be understood that changes, variations and modifications may be resorted to which fall within the scope of the-claims hereunto appended. In the drawings forming a portion of this specification.

Fig. 1 is a central longitudinal sectional view of a spark plug constructed in accordance with my invention,

Fig. 2 is a similar view of a modified form of a spark plug.

As shown in the drawings a hollow base 5 isprovided with the threaded extremity 6 and shoulder 7 adapted to be engaged with the engine cylinder in the usual and well known manner. The base 5 carries the electrode 8 spaced from an electrode 9 to provide the usual spark gap, the electrode 9 being suitably secured to a porcelain 10, as by the washers or collars 11, which are forced upon the electrode 9 and are situated within cup shaped recesses 12 formed upon the extremities of the porcelain. Intermediate its ends the porcelain 10 is provided with. a projecting annular shoulder 13 which is adapted to be clamped between a shoulder 14 provided on the inner bore of the base 5 and the lower end of a top piece 15 which is screwed into the upper end of the base, suitable gaskets 16 beingprovided to protect the porcelain.

The top piece 15 is provided with. a shoulder 17 adapted to abut the upper end of. the base 5 and the distance between this shoulder and the lower extremity of the top piece is So proportioned that the porcelain will be clamped with sufficient force to securely hold it in position, but the abutment of the shoulder 17 with the base however will prevent an excessive pressure being placed upon the porcelain and will therefore efi'ectively insure against breakage of the porcelain.

It will be noted that the ends of the porcelain 10 are equidistant from the shoulder 13 and that the electrode 9 projects from the the procelain an equal distance at each end instead of passing all the way through the plug in the usual manner. It will thus be obvious that the porcelain and electrode can be reversed in position should the lower electrode point become pitted or corroded. It will also be obvious that a new porcelain and electrode may be readily substituted whenever desired. 7

The top piece 15 is a hollow member having an annular shell like portion 18 projecting upwardly from the enlarged shoulder 17 and which portion may be provided with any suitable number of apertures 19. The lower inner wall of the top piece may be provided with a shoulder 20 against which may be seated the lower end of a sleeve 21 of any suitable transparent insulating material which projects upwardly past the apertures 19'and terminates near the top of the shell portion.

Seated against-the upper edge oi. the tr ansparent sleeve 21 is an insulating block 22 ot any suitable insulating material, having at its lower edge an, annular flange around which the top of the sleeve 18 is spun to hold the sleeve 21 and the block securely in position. An electrode 24o f anysuitable conducting material passes through the block 22 and is provided at its upper end with the usualscrew threads engaged by the thumb nut25to secure the lead wires in a common and well known manner. The lower end of the electrode 24 is in alinement with the electrode 9, with terminates a short distance above said elect-rode 9'to provide an air gap 26-to produce a condensing or intensifying effect upon the spark in a common and well knownmanner. The lower end of the insulating'block 22 is formed with a concaved cup shaped depression 27 to assist in pre venting excessive heat from the spark in directly striking the walls of the transparent sleeve 21, so as to prevent breakage thereof.

In the form shown in Fig. 2, the base block 5 is constructed in a manner similar to that shown in Fig. 1, and need not be further described Also the construction of the porcelain 10 andthe top piece 15 is similar. In the modification shownin this'ti'gure, a plurality of gaps are provided instead of the single air gap 26 shown in Fig. 1, these gaps being provided in the following manner. Theprojecting ends of the electrode 9 are reduced to form a shoulder 30 adjacent the blocki. Upon the upper reduced end of the electrode 9 is secured a. conductor of any suitable material in the form of a small round collar 31, whichis firmlypressed upon the electrode. Immediately above this elec v trode is located an insulating member 32 of similar shape and configuration and above this insulator 32 is secure'd'another conductor 33, while above this conductor is a second insulator 34, and finally a third conductor 35 islocated above the last mentioned insulator. The faces of the conductors ad j acent to the insulators are corrugated and the whole series 0 f conductors and. insulators are secured together by cement or in any other desirable manner. An insulating block 22' is carried by the upper portion of the top piece 15, said block having a flange 23 around which the upper portion of the sleeve 18 is spun in the same manner as shown in-Fig. 1. Carried by the insulating block 22 is a short electrode 24 likewise provided with a thumb screw 25 to secure the terminal wires in place. The lower end of the insulating block 22 is provided with a cup shape recess 27' and the lower end of the electrode 24 projects into said recess and when the top piece 15 is screwed into the base 5, the lower extremity of this electrode 24' abuts the upper conductor 35 with just sntiicientpressure to assist in holding the series of conductors and insulators securely in position.

The operation of the device will be ob vious, the current passing through the lead wire to the electrode 24 in Fig. 1 will have its potential raised by the condensing effect or: the air gap 26 and will surge across the gap and to the electrode 9 from the lower extremity of which the spark will jump across to the electrode 8, the intensity of the spark being greatly increased by the presence of the air gap. It will be noted that the apertures 19 with the transparent sleeve 21 provide a means to observe at an instant inspection, the passage of a spark across the gap 26 thus enabling one to ascertain immediately whether the current is being delivered to the spark plug.

Inthe form shown in Fig. 2, theoperation is somewhat similar, the current passing through the electrode 24: to the electrode 35 from the outer periphery of which a spark will jump around the insulation 345to the intermediate conductor 33 and from which in turn it will jump around'the insulator 32 to the lowermost conductor 31, thus passing in turn through the electrode 9 to jump across the gap to the-electrode 8 in an obvious manner. By using a series of insulating gaps, such as shown in Fig. 2, the capacity of the condenser is increased and consequently the intensifying effect upon the spark is increased.

Frequently the 'failure of a spark plug to function properly is caused by oil being thrown against the base of the porcelain, which oil runs down along the electrode to its point and is then carbonized by the intensive "heat of the spark, causing a deposit of carbon on the points of the electrodes which because of the insulating properties of the carbon prevents the passa e of the spark. 'The recesses 12 are providlad in the porcelain to overcome this difficulty. Oil being thrown against the base of the plug instead of flowing down along the electrode, by adhering to the. sides of therecess will flow away from the electrode as will be obvious from an inspection of the drawing.

Itwill be understood that withthe form shown in Fig. 2, that any desirable number of gaps might be provided. Itwill also be understood that while I have used the term porcelain to designate the member lOthat I donot wish to'c'on'fi'ne my'invention to the use of a porcelain: member in this connection, but as it is obvious that any desirable or suitable insulating material can be used in place of porcelain. that the term porcelain is merely used in a descriptive and notin a limiting sense.

. Having thus described my invention what I claim as new and desire to secure by Letters Patent of the United States is:

1. In a spark plug, a base, a top piece detachably secured to said base, an electrode carried by said top piece, a second electrode carried by said base, a condenser comprising a series of superposed alternately arranged conductors and insulators, interposed between said electrodes, the lower conductor of the series being secured to the first mentioned electrode, and the lower extremity of the second electrode bearing against the upper conductor of the series to assist in holding the conductors and insulators in position.

2. In a spark plug, a base, a top piece detachably secured to said base, an electrode carried by said top piece, a second electrodecarried by said base, a condenser comprising a series of superposed alternately arranged conductors and insulators, interposed between said electrodes, the faces of the conductors in contact with the insulators being provided with corrugations, means to secure said conductors and insulators in position, the lower conductors of the series being secured to the first mentioned electrode, and the lower extremity of the second electrode bearing against the upper conductor of the series to assist in holding the conductors and insulators in position.

Signed at New York, in the county of New York and State of New York, this 25th day of October, A. D. 1921.

EMIL GRAF. 

